One of the current methods of treating obesity is to reduce stomach volume by forming extended and/or multiple two-layer tissue folds in the stomach. Ideally, the method is carried so that up to one half or more of the original area of the stomach interior is sequestered in tissue folds, reducing both the volume of the stomach and area within the stomach that can interact with ingested food. This approach has the general advantages in treating obesity that (i) it is non-invasive in that it is carried out using an intra-oral stapling procedure; (ii) stomach volume can readily reduced by a desired amount, e.g., between 50-80 percent, according to the number and sizes of folds formed, (iii) the tissue folds may be formed in areas of the stomach, e.g., the fundus, that are especially susceptible to appetite control, and (iv) the procedure can be readily repaired or fine-tuned by simply by forming additional tissue folds as needed in one or more follow-up procedures.
Devices designed for treating obesity and/or gastroesophageal reflux disease (GERD) by forming stomach plications are known, e.g., U.S. Pat. Nos. 5,571,116, 5,887,594, 6,113,609, 6,159,146, and 6,592,596. Several U.S. Patents, including U.S. Pat. No. 6,663,639, and related U.S. Pat. Nos. 6,494,888, 6,773,441 and 7,736,373 disclose endoscopic methods of reconfiguring the stomach by manipulating two or more separate tissue folds. Similar methods for reconfiguring the stomach by bringing together two or more tissue folds are disclosed in U.S. Pat. No. 6,558,400, and related U.S. Pat. Nos. 7,288,099, 7,288,101, 7,510,559, 7,503,922, and 7,862,574. U.S. Pat. No. 7,175,638 also discloses and claims reconfiguring the stomach by forming pairs of tissue folds, i.e., one or more four-layer folds.
Co-owned U.S. Pat. Nos. 7,708,181, 7,721,932, 7,909,219, 7,909,222, 7,909,223, 7,913,892, 7,922,062, 7,934,631, and 8,020,741 disclose a device for forming and stapling tissue folds in the stomach. The device includes staple and anvil members that are operable to move toward and away from one another along a first axis, and arm assemblies connecting the two members and that expand outwardly, along a second axis substantially perpendicular to the first axis, as the proximal and distal members move toward one another to a tissue-capture position. The confronting faces of the two members and the arm assemblies connecting them define a tissue-capture chamber that is covered by the by a flexible-membrane sleeve having an opening through which tissue is drawn when the opening is placed against tissue and a vacuum is applied to the chamber. The device has a low-profile in a relaxed mode, for intra-oral insertion, and expands outwardly, during operation, to allow a relatively large two-layer tissue fold to be drawn into the chamber. Once a tissue fold is captured in the chamber, the device may be operated to place a ring of staples through the fold and, optionally, to form a cutout in the tissue fold within the ring of staples. One limitation of the device that has been observed, however, is that more than two layers of tissue may be drawn into the chamber, during vacuum uptake, and/or that a portion of the flexible-membrane sleeve that surround the sleeve opening may itself be drawn into the chamber, and stapled to the tissue fold.
It would thus be desirable to provide an improved device for forming a tissue fold, e.g., within the stomach, which has the advantages of the above-described device, but overcomes the current limitations in tissue uptake.